The present invention relates to an arrangement for sealing tubes or pipes.
It is known in the art to use different sealing plugs when it is necessary to seal a tube or pipe (e.g., which has sprung a leak) with minimum time expenditure. Should, for example, leakage take place in the tube then such a plug can be installed to reliably stop such leakage. In this case the plug is to be installed very quickly and effectively in the tube upstream of the point where the leakage has occurred.
It is to be understood that such a leakage can cause a lot of subsequent undesired consequences such as spreading around the broken tube liquids which are potentially dangerous to the ground water, environmental pollution, or even a flood. For example, environmental pollution may occur as a result of an accident involving damage to a tanker truck. By installing one of the aforementioned plugs one can reduce or eliminate the undesired leakage.
Such plug (see, for example, German Gebrauchsmuster 75 11 806) may include an expandable tubular casing. Both open ends of the casing are closed by rigid end plates. The plates are connected to the casing and define between their outer circumferences and the inner circumference of the tube to be plugged a small radial clearance. Such an arrangement has certain disadvantages, which reside for example from the connection of the end plates to the tubular casing of the plug by means of clamping rings. The clamping rings press the outer surfaces of the end plates and the respective end portions of the casing together. Obviously, such an arrangement is not fully reliable for repeated use since after having been used a few times such a plug tends to permit leakage rather than to stop the same. Besides, due to the required small radial clearance between the outer circumference of the end plates and the inner circumference of the tube to be plugged, the range of application of such a plug is rather limited. Should one install in the tube to be plugged a plug of too small an outer diameter there is always a danger that the rigid end plates of such a plug will take an inclined position relative to the cross-section of the tube and then the plug will then fail to provide a satisfactory seal.